[][Add Airoha EN8801S Giga Etherent phy support]

[Description]
Add Airoha EN8801S giga Etherent phy support.

1. dts example, connect 2nd GMAC to EN8801S gphy.
gmac1: mac@1 {
    compatible = "mediatek,eth-mac";
    reg = <1>;
    phy-mode = "sgmii";
    phy-handle = <&phy0>;      // add phy handler
};

mdio: mdio-bus {
    #address-cells = <1>;
    #size-cells = <0>;

    phy0: ethernet-phy@0 {
        compatible = "ethernet-phy-id03a2.9461";
        reg = <24>;            // set phy address to 0x18
        phy-mode = "sgmii";
    };
};

2. After bootup, mii_mgr command can be used to access PHY CR.
For example, reading clause 22 PHY ID
mii_mgr -g -p 18 -r 2
mii_mgr -g -p 18 -r 3

[Release-log]
N/A

Change-Id: I904afc913c9018bffb7a2a61bf643eb0e907b1d2
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/5649436
2 files changed